低温对保加利亚乳杆菌CspA基因表达影响的研究

Research of Low Temperature Treatment on Lactobacillus bulgaricus in the Expression of CspA mRNA

通过对保加利亚乳杆菌进行低温诱导处理,考察其冷休克蛋白A(cold shock proteins A,Csp A)的表达,以及菌体的冻融存活率和冻干存活率。在不同温度、不同时间条件下诱导处理保加利亚乳杆菌,利用荧光定量聚合酶链式反应(polymerase chain reaction,PCR)的方法检测诱导前后CspA的mRNA表达量;通过反复冻融,利用活菌计数法检测诱导前后菌体的冻融存活率;通过冻干试验,检测其诱导前后菌体的冻干存活率。结果表明:低温处理可使CspA的表达量明显提高,且在20℃处理4 h后CspA的mRNA表达量最高,并且菌体冻融存活率和冻干存活率显著提高。CspA可以提高保加利亚乳杆菌的冻融存活率和冻干存活率。

Through the method of low temperature treatment on Lactobacillus bulgaricus, the expression of cold shock protein CspA,freeze-thawing survival rate and freeze-drying survival rate had been investigated. Induced Lactobacillus bulgaricus with different temperature and time conditions,CspA mRNA expression before and after induction was detected by the method of quantitative PCR. Through the method of repeated freeze-thawing treatment,freeze-thawing survival rate was detected by viable count before and after low temperature treatment. Through the method of freeze-drying, the freeze-drying survival rate was detected before and after low temperature treatment. The result showed that the expression of CspA was significantly increased by the treatment of low temperature,with the treatment of 20 ℃ in 4 h,the expression of CspA was reached the highest,and the freeze-thawing or freeze-drying survival rate was increased significantly. CspA can improve the freeze-thawing or freeze-drying survival rate of Lactobacillus bulgaricus.